HTML5 Semantics

Semantic (meaningful) markup

hgroup – grouping a few headings (h1-h6) together – removed from current specification

footer – typically contains information about a section, such as who wrote it, links to related documents, copyright data etc…

nav – major navigation on the page

article – for content which can stand on its own and could be syndicated

section – thematic grouping of content. A section element is appropriate only if the element’s contents would be listed explicitly in the document’s outline. Each section can have one heading associated with it and include any number of further nested sections.

aside – content related to primary content on the page, and which could be considered separate from that content.

figure – related, stand-alone image or video

figcaption – caption for figure

time – date and time

mark – indicates text as marked or highlighted for reference purposes

small – terms and conditions, legal disclaimer

div – has no semantic meaning at all. It’s just some box, that’s going to have some information. Use for layout purposes.

Structured data – more semantic content

schema.org is a collaboration by Google, Microsoft, and Yahoo! to improve the web by creating a common vocabulary for describing data on the web. It provides a standardized way to label specific types of content. It means that search engines and other machines can read the information on the page and identify what kind of information it exactly is. Thus it can be displayed accordingly. Google recommends to use Microdata over Microformats and RDFa (answer).